Improved Alkaline Oxidation Process for the Production of Aldehydes (Vanillin and Syringaldehyde) from Steam-Explosion Hardwood Lignin

Wu, Guangxin; Heitz, Michèle; Chornet, E.

doi:10.1021/ie00027a034

Cited by 106 publications

(78 citation statements)

References 4 publications

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“…Various types of catalysts from expensive noble metals [20][21][22] to inexpensive metal ions such as iron, copper, and cobalt have been extensively studied [23][24][25][26][27] for a lignin catalytic wet oxidation process. In general, the lignin conversion rate and the yield of aromatic aldehydes are enhanced significantly in catalytic processes compared with non-catalytic processes [28].…”

Section: Introductionmentioning

confidence: 99%

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

et al. 2015

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The production of carboxylic acids by partial wet oxidation of alkali lignin was studied experimentally. The factors influencing the different types of products, their yields and concentrations were investigated. Formic, acetic, succinic, oxalic, and glutaconic acid were the main identified products. Both the temperature and oxygen partial pressure are shown to have direct effects on the product yields whereas the lignin concentration has an indirect effect. At low lignin concentrations, the yield of products was relatively high. However, at higher concentrations, the yield decreased. By measuring the lignin molecular weight distributions, it is shown that this decrease is linked to repolymerization/condensation reactions of lignin fragments which compete with oxidative lignin depolymerization.

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Section: Introductionmentioning

confidence: 99%

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

et al. 2015

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“…1), which is an analogue of vanillic acid, were obtained as the major degradation products with high yields in the above-described alkaline hydrogen peroxide treatments at high pH levels. It should be emphasized that special catalysts, such as 1,10-phenanthroline and CuSO 4 used in the previous report [24], were not employed in this study, which is significantly different from previous reports [4,24].…”

mentioning

confidence: 74%

Predominant formation of aromatic aldehyde and acid from a dimeric β-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels

et al. 2017

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“…With progressive reaction time, the yield of V reaches a plateau of 9.94% at 25 min; the yield of Sy decreases a er it passes a maximum yield of about 17% at 7 min; the yield of VA slightly increase (max at 12 min) and then decreases to a constant yield of 2.5%; and similarly, the yield of VO slightly increases (max at 5 min) and then decreases to zero a er 20 min. During the whole reaction time, negligible amounts of SA and SO was detected because the S units have higher reactivity than guaiacyl counterparts in alkaline systems (Tsutsumi et al 1995) and under conditions of O 2 or H 2 O 2 oxidation in alkaline medium (Wu et al 1994;Sultanov and Wallis 1991). We suggest the Sy is produced at higher yield, but it is promptly degraded; in the case of S units, this e ect is probably more evident due to the above mentioned reactivity of S nuclei.…”

Section: Resultsmentioning

confidence: 99%

“…It was worthy to be noticed that aromatic aldehyde such as vanillin, syringaldehyde and p-hydroxybenzaldehyde can be obtained from the oxidation process of lignin. ese aldehydes have wide applications such as avoring, chemical intermediates for pharmaceutical drugs and agricultural defensives (Wu et al 1994, Sridhar et al 2005, Sales et al 2006, Sales et al 2007). e chemical composition of lignin and its content in wood vary greatly within a plant, depending on its species, age, morphological location and growth environment.…”

Section: Introductionmentioning

confidence: 99%

La-modified SBA-15/H2O2 systems for the microwave assisted oxidation of organosolv beech wood lignin

Cheng

et al. 2012

Maderas, Cienc. tecnol.

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In this manuscript, the in uence of organosolv beech wood lignin (LOB) on its oxidative conversion to high added-value phenolic aldehydes is discussed. Environmental friendly and low-cost H 2 O 2 was used as the oxygen atom donor. e catalyst was prepared by immobilizing Lanthanum compounds onto the periodic mesoporous channels of siliceous SBA-15. e activity of the La/SBA-15 was investigated towards oxidation of LOB in the presence of hydrogen peroxide as oxidant with microwave irradiation. Considering the characteristics of LOB, an unexpected low syringaldehyde concentration at 10min of reaction time (1.47 g/L, corresponding to 15.66% yield) was obtained; the other major product was vanillin at 25min (0.78 g/L, i.e., 9.94% yield). e high reactivity of syringyl nuclei may be pointed out as the main reason for the faster production and degradation of syringaldehyde in oxidation. Other low molecular weight phenolic products were found: vanillic acid, syringic acid and minor quantities of aceto-derivatives. e pro le of products concentration with the reaction time of catalytic oxidation with microwave irradiation are shown and discussed with reference to the investigated lignin features. e mechanism of the microwave catalytic oxidation for LOB under alkaline conditions was proposed.

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Improved Alkaline Oxidation Process for the Production of Aldehydes (Vanillin and Syringaldehyde) from Steam-Explosion Hardwood Lignin

Cited by 106 publications

References 4 publications

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

Predominant formation of aromatic aldehyde and acid from a dimeric β-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels

La-modified SBA-15/H2O2 systems for the microwave assisted oxidation of organosolv beech wood lignin

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